4(e). Percussive Ornamentation

Thumb

Not so much a Celtic ornament, but a very useful technique in adding energy
and drive to an up-tempo piece, the thumb slap is executed in a way similar to a
funk bass slap. The thumb impacts the bass strings at the side of the knuckle
joint. The following pictures show before and after thumb slap positions of the
right-hand.

Fig 4.1. Bass slap – before and after

Naturally, it is easiest to use the lowest bass string to avoid interfering
with other strings. If the left-hand frets a note on the target string being
slapped, it is possible to gain some sense of that note's pitch combined with
the percussive sound. The slap is played with a short and sharp rotation of the
wrist to bring the thumb down on the string. The closer you can start the thumb
to the string, the better, as this makes it easier to hit the string cleanly. If
you take a huge swing at it, you only end up slapping the face of your guitar,
which can look a little embarrassing.

This effect is used on the Night Fishing CD and examples can be heard in
measures 26 to 56 of “The Ullapool Decision” and measure 12 of “The Potato Van”.

Back of Nail Percussive “Thwack”

Another way of creating a percussive attack on a fretted note is to use the
back of the nail of the right-hand middle finger. In this effect, the nail
starts off against the thumb. Then in a sharp movement, the nail flicks down
against the string. Figure 4.2 below illustrates this.

The difficult thing about executing this effect is to hit only one string.
This takes a lot of practice to control. On the bass strings, the effect is a
solid percussive thud. On the treble strings some interesting sounds are
possible. The effect can be either a percussive thwack, or more of a zinging
note that stands out in a run.

Fig 4.2. Percussive thwack – before and after

Middle Finger Thud

This technique produces a mild percussive thud sound, and is useful in
creating a simple backbeat for a section. Covering 2 notes, the technique is
notated with an X, followed by an open-string for the following note. For
example, see the tablature for the song “Any Day Now”, starting at measure 20.
Instead of plucking the first note marked X, the right-hand middle finger lands
on the string with the fleshy part just below nail to give a light thud sound.
The following note is the sounding of this open string, voiced by lifting the
middle finger from the string and giving a very slight flick on the way off. As
the skin leaves the string it will give enough movement to give the string
vibration.

The technique is used extensively in the tune “Kettle of Fish”, where the
thud is voiced at the same time a bass note is being plucked with the thumb. For
example, see the second note of measure 2. In this case the thud is quite
subtle, and is voiced as a combined movement with the plucking thumb. It is
important to keep the right-hand very relaxed. This example is probably best
left until after the sections at the end of “Any Day Now” (measure 20) and “All
At Sea” (measure 68).

This topic is not covered in detail here, but take a look at the
scrapbook page for an article
with some examples and a video demo.